Bald 1960 Peromyscus eremicus Oct. 25 E side Isla Cerralvo, Baja Calif., Mexico - In 15 mus. special + 2 rat traps set in the dark last night, baited with walnut, caught 8 deer mice. In the evening, just after dark, got one more. Left traps out, reset but not Oct. 26 rebaited, and had another in the morning. That is a total of 10, of which 6 were put up by copper out. The area of the traps was the arroyo near camp, about 25 x 50 yds. Traps were set on the perimeter of this area only, on rocky ledges or near rocks with burrows (holes) nearby. Oct. 27. In a line of 35 traps on a bushy hillside, netting the stream bed at both ends, caught 6 Peromyscus. Putting up 3. One had a large (@ 25mm long) larva of a botfly on its side - the mouse weighed 20.3 gm. As I write these notes, a mouse is running around our food supply. Oct. 28 In this same line had only 2 mice. In 5 rat traps on the ridge facing the sea, had 4. Two of these were badly chewed up, one probably by a raven or vulture. In the evening, set 1 trap near our supplies. So far, in a little over two hours, have caught 2 mice - 4♂♀, 2 @♀♀, 1♂, 1♀. 5 minutes later, got another ♂, and 2 or 3 minutes later again a mouse sprung the trap but escaped. Within 2 minutes, had another ♀. After 10 mice in 1 spot in about 3 hrs, left the trap un-set.